In 1878, Paul Broca defined the limbic (Latin limbus:border)
lobe as the cerebral convolutions that surround the brain stem and
central commissures consisting primarily of the parahippocampal and
cingulate gyri. In 1937, Papez suggested the limbic lobe was part of a
larger integrated system involved in emotional behavior that is now
referred to as the limbic system. Different authors have defined its
components in various ways, but the main structures include the cingulate
gyrus, the parahippocampal gyrus, the hippocampal formation, the
hypothalamus, the septal nucleus, the amygdala, the mammillary bodies,
several thalamic nuclei, the basal forebrain, olfactory structures, and
the subcallosal region as well the tracts connecting them.